Electrical power transmission.



J. G, P. TEOMAS. ELECTRICAL POWER TRNSMISSION. Rp APPLIOMION FILEDmm2/1. 1910. 4968,290. vPatented Aug. 23, 1910.

lUNiiED sTATEs PATENT' oEEicE.

JOHN GonrnEY BARRY THOMAS, or cniswicx, ENGLAND.

ELECTRICAL POWER TRANSIVIISSION.`

i Specication of Letters Iatent. PatentedAug. 23, 1910; Applicationfiled January 24, v1910. Serial No. 539,708.

THOMAS, a subject of the King of Great Britain, residing at 21-Ennismore avenue, Chiswick, in the land,- engineer, have invented newand useful Improvements in Electrical Power' Trans. missicn, of-whic'lithe following isa specification. 'p p This invention relatestothe class of 'electromechanical transmission systems described in mPatent No. 948,486 patented February Sti, 1910, in Whichthe prime motorand two dynamo electric machines are mechanically interconnected through.three members of a gearing so that the speed of each machine -isdetermined by the speeds of the'reinaining two.

The object of the present invention is to modifysystems of this kind soas. articularly, to'vsuit them to the driving o trains, whether on roador rail. When such asystem is ap lied to -a train the dynamoconnected-wit the wheels is replaced by several separa-te -machinesdistributed .over the varions vehiolesthat one or moi'e axles on all oron most-of the vehicles may be a driving axle. It/is obvious then thatthe transmis- Y lsionof vpower electrically to the'l dynamo electricmachines thus distributed may involve a serious loss particularly whenthe power so -transmitted is large, and moreover the transmission ofthe' large currents is in itself a matter of difficulty. According tothe present invention means are provided upon vthe front oi' mainvehicle for eliminating .thedistributed dynamos at times when the powerIrequired to be transmitted would become particularly large.

In the accompanying drawings-Figure 1 illustrates the a plica'tion ofthe invention to a system in wtiich an internal combustion engine is theprime motor, and Fig. 2 its application to a system having a battery asits source of energy.- Fig. 3 is a diagram of the connections used 'inconjunction with the ap4 aratus o- Fig. 2.-

n Fig. 1, 1 is the prime motor driving through the shaft 2 a gearingwhich coniprises-a casing?) supportin `sets of double gearing with thesun wheel 6 and the larger piniensvwiththe sun vwheel 7. Of these sunwheelsthe former is connected to theshaft 8 .whichextends to the roadwheels and' carcounty of Middlesex, Engries the, armature 9 of a dynamoelectric machine 9;- 10, 1Q indicating the field; the latterl is on asleeve 11 carrying the armature '12 of a dynamo electric machine 12, 13.

Upon the sleeve is a drum 14 withy a brake band 15 by. means of which itmay be held L stationary, and clutch parts 16, 17 on the sleeve 11 andshaft 8 respectively permit these two parts to be enga-ged together.

These are the members constituting the system described in my earlierpatent, and aceording to the present invention there is added to them adynamo electric machine comprising the armature 18, and field-19, theformer being secured directly on the lshaft 2 of the prime motor 1.

VIn the system of transmission described for example in my Patent No.948,436 patented Feb. 8th, 1910, the regulation is effecvted in'thefollowing manner: The veliicl on which thevparts are mounted is starteby giving the field 13 a small excitation, the field 10 being stronglyexcited. To increase the speed the field 13 is strengthened and thefield 10l weakened, until a condition of affairs is reached in which thearmature 12 is rotating very slowly lin a strong field and the armature9 quickly in a very weak field. After the armature l2 has been heldstill mechanically by the use of the brake device 14, 15, if this deviceis employed, further increase of Speed is obtained by reversing thefield 10, so that the machine 9, 10 acting as a generator drives themachine 12, 13, as a motor. Strengthening of the field 10 in thisreverse direction and weakening of the field 13 continues the increaseof speed until the shaft 8 is lrotating at the same speed as the sleeve11, when the clutch parts '16 and 17 may be brought together to avoidthe electrical transmission of power between the machine 9, 10 and 12,13.

According to the resent invention the machine V18, 19 is substituted forthe machine 9, 10 at the stage when the latter reversesA its functions,the 4machine, 9, 10 being put .on open circuit or otherwise renderedinactive. The` speed increase 'is efected in the correspondlng mannervby increasingthev field 419 until the shaft 8 and sleeve 11 attain'acommon speed. If desired, of course, this speed may lie-exceeded, (theclutch parts 16, 17 being leftdisengaged) by decreasing the field 13.Where this system is applied -to the driving-of a train the prime motor1 and onlyone half instead of the whole of the' power is beingtransmitted electrically, and therefore the losses in transmission, toavoid which the clutch was employed. in the older systems, are'not soserious.

In addition to its function asa generator 'in connection with thetransmission of power, the machine 18, 19 may be used for otherpurposes. A battery ofaccumulators can be carried on the locomotive, andthese coupled to the machine 18, 19 will serve to lsupply power forstarting up the prime motor 1 or to assist it when'the vehicle isascending steep gradients. The machine 18,

19 may also be usedfor charging up the ac' cumulators when the'fu'llpower of thezen gine ylis not required at the roadl wheels.

Where as'inFigs. 2 and 8 a battery v20- isthe' source of power drivingthe, vehicle by supplying an'ordinaiyv motor 21, 22, the

invention may, be applied still vmore easily because there is no need toadd an extra dynamo electric machine.V A little consideration'willshowthat the machine 18, 19 -in Fig. 1 has simply-the purpose ofenabling the prime motor Lto supply the energy required by the machine12, 13, when it has reversed its unction.1 y vThe source of energy now'being the battery there is no need for any transformation of the form'of energy, but the 'battery 20 can itself be directly con- I nected tothe. machine 12, 13. VTo imitate 4tion of switches necessa for such,gradual the action of the machine 18, 19, it would be necessary, whenthe current in the armature 12 is to be reversed, to connect the batteryto this armature cell by cell, so as to gradually increase the-voltage aplied just as is effected by increasing the .e d 19 from zero. Inpractice, however, the --complicaaddition hardly just' ed. The machine12,18fistherefore allowed to reverse its fungtionand regulation -iscontinued as in `the older Ysystems untill-.the .voltage 'of' themachine 9, 10 whichisrapplied to? 'the machine-'.12, is equal .tothat-'of the battery. At this oint the former machine laced big-theattery at one "Step" Natlral ythe .l .60 C a nge -of connectionsrequisitefor this purpose would be effected like all theother changesinthe systemA by means of a controller'of ordinarytype.

In the case of Fig. 2 als'othe system has the same advantage as-beforelover the older contact, negative pole of battery system when used on asingle vehicle,

namely that the clutch 16, 17 becomes unnecessary, and in thiscasenotmerely unnecessary but quiteusele'ss.

It is of advantage when the prime source of energy is electrlcal to sodesign the machines 9, 10,' and 12, 13, that their voltage equals thatof the supply before the two machines have attained a common speed.

As soon as the change of connections described has been made the vehiclehas really a direct drive, and a further increase'of speed can now beattained Awith this direct .drive by weakening the field 13, thisincrease extending, if desired, beyond the point-,of common speed.

It will be` notedthat the system of Fig. 2

arm, left middle contact of' switch 55, mal

chine 12, 13 switch arm, right lower coniel 13 is strengthened bycutting out the rheostat 50, and field 10 is weakened by the insertionof the rheostat 51. The time then comes for reversal; to eiect which,switch Y 54, is thrown over, so that the polarity of machine 9, ischanged. (This is obviously the same, in e1i`ect,as changing over theconnections between the two armatures and leaving the sign of the eldsand the polarity unaltered.) Field 10 is` then again built up and iield1'3 is weakened by reversely o per brush of armature 12, middle leftcontact of switch 55,|switch arm, upper left 20, positive pole,upperrightvcontact of switch 55, switch arm, middle rightfcontact, andlower brush of armature 12.1 Rheo'stat '52 may. be employed to -vary the'current between the machines or the' supply ,from battery 20. In thisFig. 3 mach1ne'9 hasto be disconnected from machine l12 before thelatter is joined to thebatteries 20, e., a circuit car-- r ying currenthas to be interrupted.

What I claim 1. In an electro-mechanical system of powertransmissiol'nthe' combination with a prime motor, of two dynamoelectric .machines, gearing connecting said motor and machines so thatlthe speed of each machine depends on that vof the others, a separate.source of electrical power and means for tact and upper brush ofarmature 9. The

@sasso connecting one of said machines to the other or to the separatesource. l 4

2. In. an electromechanical system of power transmlsslon, thecomb-matlon wlth a prime motor, of two dynamo electric ma' chmes,gearing connectlng sald motor andy machines so that the s eed of eachmachine depends on that of t e others, a battery,

lmeans for-causing one machine to generate current and supply the other,and means' for subsequently disconnecting the machines and joining thegeneratorto the'l battery.

3. In an electromechanical system of power transmission, the combinationwith an electrical source of j ower, `of anA elec-l trical prime motor,two ynamo electric ma- -chines, gearing connecting said machines tooneof said dynamo electric machines to the other or to the electricalsource of power.

4. In an electro-mechanical system of power transmission, thecombination with a prime motor, of two dynamo electric machines, gearingconnecting saidmotor and machines so that the speed of each machinedepends on that of the other two, means for enabling one of saidmachines to generate current and supply the other electrically, andmeansfor dlsconnectin said machines A and for supplying electrica' energy toone `of the'separate machines;

Intestimony whereof -I have signed my vname to this' specification inthe presence of twosubscribingwitnesses, A

- JOHN GODFREY PARRY THOMAS.

1Witnesses:

ALFRED STILL,

WILLIAM Hom.

